Researchers found that the same hormone, oxytocin, spikes in both human and
canine brains when a dog is gazing at its owner

Humans love their pet dogs in the same way as they do their children, and the feeling is mutual, scientists have discovered.

Researchers found that the same hormone, oxytocin, spikes in both human and canine brains when a dog is gazing at its owner.

Oxytocin is known to play a strong role in triggering feelings of unconditional love and protection when parents and children look into each other’s eyes or embrace.

So the findings suggest that owners love their pets in the same way as family members, and dogs return their devoted affection.

"These results suggest that humans may feel affection for their companion dogs similar to that felt toward human family members, said Dr Miho Nagasawa, from the department of animal science at Azabu University in Sagamihara, Japan.

"Oxytocin plays a primary role in regulating social bonding between mother and infants and between sexual partners."

The researchers from the University of Tokyo and Duke University in the US believe that oxytocin creates a ‘neural feedback loop’ that has strengthened the bond between man and ‘his best friend’ for millennia.

To test the theory, researchers put dogs in a room with their owners and documented every interaction between them, such as talking, touching and gazing.

They then measured levels of oxytocin in urine and discovered that increased eye contact between dogs and humans had driven up levels of the hormone in both species.

However when they performed the same experiments on wolves which had been raised by humans there was no spike in oxytocin, suggesting it evolved during the domestication process which began around 34,000 years ago.

Animation: The Nagasawa experiment explained

Dr Evan MacLean, a senior research scientist at Duke University said that dogs had learned to ‘hi-jack’ the bonding pathway between parents and their children: “It’s really only in the last couple of thousand years that we have kept dogs as pets, and dogs began to be able to relate to humans in meaningful social ways.

“They became attuned to our social cues in the way that young children are. For example when dogs are presented with an impossible task they quickly turn to humans to see what to do, just like children do. Wolves don’t do that.

“Our relationship with dogs are very much like parent child relationships. We respond to our dogs quite a bit like human children. Brain imaging studies have shown that brain networks of mothers respond in the same way to pictures of their own dog to their own children.

“One evolutionary scenario might be that dogs found a way to hijack these parenting responses and dogs over time may have taken on more childlike and juvenile characteristics to further embed themselves into our lives.”

Watch: Experiment 1

The researchers say that the paper shows that dogs feel like a child of the family, rather than the underdog in a pack.

“I think the results of this paper wind very well with the parent, child model given that we know that oxytocin plays such an important role in parents bonding with their children,” added Dr MacLean.

In a second experiment, the researchers sprayed oxytocin directly into the noses of certain dogs and placed them in a room with their owners and some strangers.

Watch: Experiment 2

Female dogs responded to the treatment by increasing the amount of time they gazed at their owners.

After 30 minutes, oxytocin levels had also increased in the owners of the treated dogs, the researchers report, providing further evidence for the feedback loop between owner and canine.